Ethanol is a particularly valuable alcohol that has a broad range of applications such as chemical solvents; feedstocks for various chemical syntheses; consumable products, e.g., beer, wine, and spirits; and fuels.
The hydrogenation of alkanoic acids and/or other carbonyl group-containing compounds is one method of producing alcohols such as ethanol. This method has been widely studied. As a result, a variety of related combinations of reactants, catalysts, supports, and operating conditions have been mentioned in literature.
Anhydrous ethanol, however, is preferred for some ethanol applications, e.g., fuels. Anhydrous or substantially anhydrous ethanol, however, is often difficult to obtain from conventional hydrogenation and separation processes. For example, the ethanol and water produced in conventional hydrogenation reactions may form a binary azeotrope. This azeotrope contains about 95% ethanol and about 5% water. Because the boiling point of this azeotrope (78° C.) is just slightly below that of pure ethanol (78.4° C.), an anhydrous or substantially anhydrous ethanol composition is difficult to obtain from a crude ethanol composition via simple, conventional distillation.
Even though some hydrogenation and separation techniques may be known, the need exists for an improved process and system for producing anhydrous ethanol compositions.